BLENDER & FBX Mocap Import not translating to Rig
In Motion Builder, when you add or change a reference object for a bone its rest pose is altered. This behaviour leads to a new rest position from which the animation is calculated.
A solution could be to set a keyframe on every bone in motion builder in its new rest pose, save it as FBX, import in Blender, apply this static animation, go to pose mode, select all bones and press ctrl A &quot;Apply pose as rest pose&quot;, then use this rig to perform the real animation.